Nicholas Schofield

UNSW Sydney | UNSW · Water Research Centre (WRC)

The freshwater resources of Oceania are highly variable, comprising some of the global extremes in terms of availability and access. The Pacific Island Countries and Territories (PICTs) have lower water security than Australia and New Zealand, the two developed nations in the region. Among PICTs, whilst surface and groundwater resources are availab...

In this final chapter, we synthesise key lessons learnt from practical experiences addressing climate risks to water security across the Asia Pacific. While concerns for climate change impacts are clearly growing, policy responses must further embrace the multi-sectoral and cross-scalar nature of risks to water security. In the various socioecologi...

This chapter introduces the scope, the approach and focus of the book, which aims to deepen our understanding of how various sub-regions and localities in the Asia-Pacific region are facing the intensifying impact of climate change. This chapter clarifies our interdisciplinary and practice-oriented approach to understanding and tackling questions a...

A review of the impacts of climate change on water security, the effectiveness of policy responses and the way forward from local to national to regional scales across the Asia Pacific.

Since European settlement, the development of Australia's land and water resources has adversely affected river health through: altering flow regimes; decreasing water quality; reducing or impairing riparian and instream habitat and loss of aquatic biodiversity. Early in the 1990s the Australian Government established the National River Health Prog...

Environmental water allocation is a critical issue in Australia and internationally. It has been prominent in Australia for a little over ten years during which time major policy and scientific advances have been made, but little implementation. This paper examines current understanding of environmental water allocation across a broad range of disc...

Conventional wisdom has it that we already have enough science to address the problems causing degradation of our environment, including rivers. This is not true. However it is the case that we could be using existing knowledge better, and that we could be doing more to learn the lessons from the huge sums being spent on river restoration and manag...

Pesticides are used extensively in cotton production and their presence in the river system in northern New South Wales and Queensland is well documented. This paper describes a major R and D Program to determine the transport and fate of cotton pesticides and their impact on aquatic biota. Pesticides were shown to move on-farm mainly due to runoff...

Large infiltration ponds (10–15 m2) were used, in conjunction with a ring infiltrometer and a well permeameter, to determine the infiltration characteristics of a complex lateritic soil profile in the jarrah (Eucalyptus marginata) forest of Western Australia. Simultaneous measurements of soil water content and soil water potential allowed a descrip...

Dryland salinity is emerging as a major form of land and water degradation in southern Australia, particularly in Western Australia, South Australia and Victoria, and to a lesser extent in New South Wales, Tasmania and Queensland. Tree planting, in combination with other vegetation treatment, is regarded as a leading solution to dryland salinity. R...

Land and stream salinisation in Western Australia has occurred as a result of the clearing of native vegetation for agricultural development. One approach to controlling the salinisation, extensive reforestation, has been tested on a site which was 35% cleared and converted to pasture in the 1950s. By 1979 saline ground water was discharging in the...

A small (344ha) experimental catchment in southwest Western Australia was partially deforested (western 53% of the catchment) in 1976 to study the effects of agricultural development on water quantity and quality. The impact on the groundwater system in the cleared area was dramatic. Initial rates of rise were only 0.11 m year−1 but this increased...

A small (300 ha) experimental catchment in a high salt storage landscape in southwest Western Australia was subject to several different clearing treatments to determine their respective impacts on groundwater levels.Within subcatchments that were 60–70% cleared, groundwater level rises were observed of 7.8–10.2 m compared with a 5.8 m rise with 32...

Stream and land salinisation brought about by rising groundwater levels due to the clearing of native forest for agricultural development is a major environmental and resource problem in Western Australia and several other semi-arid regions of the world. One potential approach to reclamation with simultaneous economic benefits is agroforestry. To d...

A small forested catchment in southwest Western Australia was thinned to study the effect on hydrology, wood production and disease escalation. This paper deals primarily with the hydrological aspects. The uniform, intensive thinning treatment reduced crown cover from 60 to 14%, which resulted in an increase in streamflow of approximately 20% of an...

Dense planting of selected trees in salt-affected valley floors and non-saline adjacent slopes has been evaluated as one strategy for controlling rising saline groundwater under agriculture. Of the 127 ha experimental catchment, 44% had been cleared of native forest in the 1950s. Valley reforestation covering 35% of the cleared area took place in 1...

Replacement of deep-rooted perennial vegetation with annual crops and pastures has led to rising groundwater tables and transport of previously stored salts to streams in south-west Western Australia. Trials to determine the potential of various reforestation strategies to reverse this process by lowering the groundwater table were commenced in 197...

A new constant head well permeameter has been designed to measure saturated hydraulic conductivities (Ks) ranging from 10−6 to 10−3 ms−1. Application to shallow soils of Western Australia in this Ks range highlighted problems with different aspects of the borehole discharge response. Firstly steady-state borehole discharge was only reached in 13 ou...

Seasonal soil water dynamics were measured at a fine-textured, upslope site within the jarrah forest of southwest Western Australia and compared to the results from a coarse-textured hillslope transect. Gravity drainage dominated during winter and early spring. This reversed in early summer and an upward potential gradient was observed to 7 m depth...

Seasonal soil water dynamics were measured on a hillslope transect in the jarrah forest of southwest Western Australia over the period 1984-86 using mercury manometer tensiometers, gypsum blocks, and a neutron moisture meter. The soil water potential gradients indicated downward vertical drainage flux through winter and spring. There was generally...

Two methods of estimating reforestation area for salinity control are described. The first method, a simple water balance model, has readily determinable parameters and sensitivity. Further parameter measurements are necessary to improve its reliability and applicability. The second method is based on regressions of observed water table reductions...

An in situ calibration procedure for complex lateritic soils of the jarrah forest of Western Australia is described. The calibration is based on non-destructive sampling of each access tube and on a regression of change in water content on change in neutron count ratio at 'wet' and 'dry' times of the year. Calibration equations with adequate precis...

Stream salinities in southwest Western Australia are strongly influenced by land use, soil salt storage and rainfall. The salinities of forest catchments are fresh and have declined over the last two decades due to decreasing groundwater solute discharge under lower than average rainfall conditions. Catchments extending to or lying in lower rainfal...

The development of new surface water sources to meet the growing demand of the Perth Metropolitan Area is becoming increasingly costlyy because most of the readily available surface water sources in the jarrah (Eucalyptus marginata Don ex Sm) forest have been utilised. There is also growing concern that the Greenhouse Effect will significantly redu...

The clearing of native vegetation and establishement of agricultural plants on a small catchment in southwest Western Australia resulted in a large streamflow increase (∼30% rainfall yr−1). This increase was brought about by a decrease in transpiration and interception loss. Streamflow increased markedly in the first year after clearing (∼10% rainf...

In a global sense the hydrology of the jarrah forest is unique in producing little streamflow from moderate rainfall. This is attributed to the large soil water storage capacity of the forest soils which jarrah is well adapted to exploit during summer. The sequence of high winter rainfall accompanied by soil water storage, followed by high summer e...

A model developed by A. J. Peck to predict the effects of land disturbances on stream salinity has been extended to take account of increased stream runoff, and applied to the jarrah forest region with improved parameter estimates. Validation on Wights experimental catchment suggests that the model is capable of reliable predictions in the case of...

Wilson Inlet is a ‘bar-built’ estuary, open to the ocean only when a sandbar has been breached after river flow. estimates are presented of phosphorus and nitrogen loadings from rivers, losses to the ocean, and amounts present in estuarine components during a particular year. Following bar opening, a volume of water equivalent to 35% of estuarine v...

A previously developed model has been tested on three catchments: Crimple Beck (8 km2) near Harrogate, Hodge Beck (36 km2) on the North York Moors and the Wye headwater (10.5 km2) in central Wales. The model was originally validated on subcatchments within Crimple Beck. For this study forecasts were made over a period of one year, based only on rai...

The early evolution of a Jupiter-like protoplanet is simulated by constructing a physically detailed computer-based model which solves the equations of hydrodynamics and radiative energy transfer for the spherically symmetric case. The model is specifically developed to study the initial and boundary conditions relevant to the capture theory for th...

An intricate point-mass simulation of early protoplanetary evolution in the tidal field of the Sun, and under physical constraints appropriate to the Capture Theory, shows that a Jupiter- like protoplanet which is moving on a highly eccentric orbit passes through a series of prolate spheroids until self-gravitation restores the protoplanet towards...

The formation of the earth by accretion from a uniform Keplerian dust disk is numerically investigated, with particular reference to the consequences of particle interactions within the planetary sphere of influence. For a given set of parameter values a planet of earth mass is seen to form in a short time with a prograde angular momentum of magnit...

European settlement of south-west Western Australia, which contains 90% of the State's population, has been characterised by the development of a vast agricultural industry. Agricultural development necessitated the conversion of native, perennial, deep-rooted vegetation to annual, shallow-rooted pastures and crops. This strongly disturbed the wate...